Getting day, month and year apart from Db

Dear all.
I want to select the day, month and year from a SQL date field, so with the structure as 2018-03-09.
To keep using that example, I want to do this: select the day (= 09), the month (= 03) and the year (=2018) apart from eachother, so that I can edit them without having to edit the entire field.
I want to do that, because I want to echo the values as a value in a text form field...
I hope someonecan help me with this problem.
Thanks in advance.